[PATCH v2 1/2] mtd: brcmnand: iProc big endian and ONFI support

[Ray Jui]

This patch adds big endian and ONFI support for various iProc based
SoCs that use the core brcmstb NAND controller

This patch was originally implemented by Prafulla Kota
<prafulla.kota@xxxxxxxxxxxx> and fully tested on iProc based NS2 SVK

Signed-off-by: Prafulla Kota <prafulla.kota@xxxxxxxxxxxx>
Signed-off-by: Ray Jui <ray.jui@xxxxxxxxxxxx>
---
 drivers/mtd/nand/brcmnand/brcmnand.c   | 12 ++++++------
 drivers/mtd/nand/brcmnand/brcmnand.h   | 13 ++++++++-----
 drivers/mtd/nand/brcmnand/iproc_nand.c | 18 ++++++++++++++----
 3 files changed, 28 insertions(+), 15 deletions(-)

diff --git a/drivers/mtd/nand/brcmnand/brcmnand.c b/drivers/mtd/nand/brcmnand/brcmnand.c
index b76ad7c..12a1585 100644
--- a/drivers/mtd/nand/brcmnand/brcmnand.c
+++ b/drivers/mtd/nand/brcmnand/brcmnand.c
@@ -1279,7 +1279,7 @@ static void brcmnand_cmdfunc(struct mtd_info *mtd, unsigned command,
 		u32 *flash_cache = (u32 *)ctrl->flash_cache;
 		int i;
 
-		brcmnand_soc_data_bus_prepare(ctrl->soc);
+		brcmnand_soc_data_bus_prepare(ctrl->soc, true);
 
 		/*
 		 * Must cache the FLASH_CACHE now, since changes in
@@ -1292,7 +1292,7 @@ static void brcmnand_cmdfunc(struct mtd_info *mtd, unsigned command,
 			 */
 			flash_cache[i] = be32_to_cpu(brcmnand_read_fc(ctrl, i));
 
-		brcmnand_soc_data_bus_unprepare(ctrl->soc);
+		brcmnand_soc_data_bus_unprepare(ctrl->soc, true);
 
 		/* Cleanup from HW quirk: restore SECTOR_SIZE_1K */
 		if (host->hwcfg.sector_size_1k)
@@ -1508,12 +1508,12 @@ static int brcmnand_read_by_pio(struct mtd_info *mtd, struct nand_chip *chip,
 		brcmnand_waitfunc(mtd, chip);
 
 		if (likely(buf)) {
-			brcmnand_soc_data_bus_prepare(ctrl->soc);
+			brcmnand_soc_data_bus_prepare(ctrl->soc, false);
 
 			for (j = 0; j < FC_WORDS; j++, buf++)
 				*buf = brcmnand_read_fc(ctrl, j);
 
-			brcmnand_soc_data_bus_unprepare(ctrl->soc);
+			brcmnand_soc_data_bus_unprepare(ctrl->soc, false);
 		}
 
 		if (oob)
@@ -1678,12 +1678,12 @@ static int brcmnand_write(struct mtd_info *mtd, struct nand_chip *chip,
 		(void)brcmnand_read_reg(ctrl, BRCMNAND_CMD_ADDRESS);
 
 		if (buf) {
-			brcmnand_soc_data_bus_prepare(ctrl->soc);
+			brcmnand_soc_data_bus_prepare(ctrl->soc, false);
 
 			for (j = 0; j < FC_WORDS; j++, buf++)
 				brcmnand_write_fc(ctrl, j, *buf);
 
-			brcmnand_soc_data_bus_unprepare(ctrl->soc);
+			brcmnand_soc_data_bus_unprepare(ctrl->soc, false);
 		} else if (oob) {
 			for (j = 0; j < FC_WORDS; j++)
 				brcmnand_write_fc(ctrl, j, 0xffffffff);
diff --git a/drivers/mtd/nand/brcmnand/brcmnand.h b/drivers/mtd/nand/brcmnand/brcmnand.h
index ef5eabb..5c44cd4 100644
--- a/drivers/mtd/nand/brcmnand/brcmnand.h
+++ b/drivers/mtd/nand/brcmnand/brcmnand.h
@@ -23,19 +23,22 @@ struct dev_pm_ops;
 struct brcmnand_soc {
 	bool (*ctlrdy_ack)(struct brcmnand_soc *soc);
 	void (*ctlrdy_set_enabled)(struct brcmnand_soc *soc, bool en);
-	void (*prepare_data_bus)(struct brcmnand_soc *soc, bool prepare);
+	void (*prepare_data_bus)(struct brcmnand_soc *soc, bool prepare,
+				 bool is_param);
 };
 
-static inline void brcmnand_soc_data_bus_prepare(struct brcmnand_soc *soc)
+static inline void brcmnand_soc_data_bus_prepare(struct brcmnand_soc *soc,
+						 bool is_param)
 {
 	if (soc && soc->prepare_data_bus)
-		soc->prepare_data_bus(soc, true);
+		soc->prepare_data_bus(soc, true, is_param);
 }
 
-static inline void brcmnand_soc_data_bus_unprepare(struct brcmnand_soc *soc)
+static inline void brcmnand_soc_data_bus_unprepare(struct brcmnand_soc *soc,
+						   bool is_param)
 {
 	if (soc && soc->prepare_data_bus)
-		soc->prepare_data_bus(soc, false);
+		soc->prepare_data_bus(soc, false, is_param);
 }
 
 static inline u32 brcmnand_readl(void __iomem *addr)
diff --git a/drivers/mtd/nand/brcmnand/iproc_nand.c b/drivers/mtd/nand/brcmnand/iproc_nand.c
index 585596c..4c6ae11 100644
--- a/drivers/mtd/nand/brcmnand/iproc_nand.c
+++ b/drivers/mtd/nand/brcmnand/iproc_nand.c
@@ -74,7 +74,8 @@ static void iproc_nand_intc_set(struct brcmnand_soc *soc, bool en)
 	spin_unlock_irqrestore(&priv->idm_lock, flags);
 }
 
-static void iproc_nand_apb_access(struct brcmnand_soc *soc, bool prepare)
+static void iproc_nand_apb_access(struct brcmnand_soc *soc, bool prepare,
+				  bool is_param)
 {
 	struct iproc_nand_soc *priv =
 			container_of(soc, struct iproc_nand_soc, soc);
@@ -86,10 +87,19 @@ static void iproc_nand_apb_access(struct brcmnand_soc *soc, bool prepare)
 
 	val = brcmnand_readl(mmio);
 
-	if (prepare)
-		val |= IPROC_NAND_APB_LE_MODE;
-	else
+	/*
+	 * In the case of BE or when dealing with NAND data, alway configure
+	 * the APB bus to LE mode before accessing the FIFO and back to BE mode
+	 * after the access is done
+	 */
+	if (IS_ENABLED(CONFIG_CPU_BIG_ENDIAN) || !is_param) {
+		if (prepare)
+			val |= IPROC_NAND_APB_LE_MODE;
+		else
+			val &= ~IPROC_NAND_APB_LE_MODE;
+	} else { /* when in LE accessing the parameter page, keep APB in BE */
 		val &= ~IPROC_NAND_APB_LE_MODE;
+	}
 
 	brcmnand_writel(val, mmio);
 
-- 
2.1.4